Its discovery was no help to them, since it was far too small to admit the spider. "Go on!" Dworn ordered doggedly. "At least we know now that _their_ dwelling can't be far!" Qanya glanced briefly sidelong at him, then moved the levers, and the spider rocked upright once more and began to climb. * * * * * The sun was low, and the shadows of rocks and dunes in the valley behind them were pointing long blue fingers eastward, when the machine staggered up the last precipitous ascent and stood on level ground at the summit. Dworn took a deep breath and looked ahead, looked for the first time in his life upon the unknown land beyond the Barrier. At first glance, it differed little from any of the desert country where he had lived all his life. The ground shelved gradually away from the rocky rim on which they stood; far off, against the darkening eastern sky, blue mountains rose murkily, but between here and the ranges lay a vast shallow depression, an arid sink floored with wind-rippled sand. Perhaps it had been a lake-bed once, before natural or unnatural cataclysms, and the millennial drying-up of all this country, had emptied it of water. Or perhaps--as its circular form suggested--it was one of those other, mysterious depressions which were scattered irregularly across the face of the earth where no lakes had ever been; those, legend said, were scars left by the ancients' wars. The rich light of the declining sun fell at a shallow angle into the miles-wide bowl and brought out with startling clarity the maze of wheel-tracks, crossing and criss-crossing, which covered its sandy expanse and testified to a fever of recent machine activity there. The light gleamed, too, here and there, upon scurrying metallic shapes, that raced by ones and twos or in trickling columns to and from the center of the bowl, where-- Dworn strained his eyes and his capacity for belief in an effort to make sense of the structures there, miles away. He was not very successful, for the scene was too unlike anything he had ever looked on before. There were certain races which built stationary dwellings--Dworn knew of the scale-makers who lived, in colonies sometimes of considerable size, beneath individual armored, anchored domes sunk into the face of some impregnable rock; he knew of the sand devils with their pits, and now he had seen also how the spider people nested. But the huge buildings that loomed yonder, lowering and windowless, and the winged things clustering thick on the ground about them, were such as he had never seen in his nomadic life.